Manufacture of charcoal.



0* WRIGHT.

MANUFACTURE OF CHARCOAL.

APPLICATION- FILED AUG. 1, 1912.

l ,QQQA 18., Patented Apr; 7, mm

FIGZ:

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oscaawmen'r, or PENNANT HILLS, mun SYDNEY, new scorn wanes, ens'reahte.

MANUFACT RE or CHARCOAL.

Specification of letters Patent. Application filed August 1, 1912- Serial N0. 712,731.

Patented a st. rate.

To all whom it may concern:

Be it known that I, OSCAR WRIGHT, a subject of the King of GreatBritain and Ireland, residing at Park Road, Pennant Hills, near Sydney, in the State of New South Wales, Australia, have invented certain new and useful Improvements in the Mann facture of Charcoal, of which the followin is a specification.

his invention relates to the manufacture of charcoal and has been devised with the object of obtaining a maximum percentage of charcoal of high grade and uniform quality and a minimum percentage of ash.

Heretofore charcoal has been burned in covered heaps and in meilers and kilns and in some cases in chambers constructed of iron sheets or plates, these plates being in certain known constructions of said chambers lined with a refractory substance such as firebrick or asbestos millboard. The air vents and smoke ventsjhave been variously arranged in these chambers.

The present invention is a process characterized by the manner of manipulating the drafts in a kiln of certain construction during the burning rocess therein, whereby the improved 'e ects before mentioned are attained.

The kiln is preferably constructed of metal plates or sheets riveted together and is most conveniently made in rectangular form and used standing vertically. But it may be made of vertical cylindrical or oval form. It need not be closed at the bottom as a sufficiently good closure thereat may be obtained by erecting the kiln on the ground and banking clay or soil around the foot of it. The top or cover plate of the kiln is'most conveniently made detachable, so that it may be readily fitted to the body of the kiln and the joint closed by luting with clay or earth after the charge has been inserted. If it is not made detachable, means such as close fitting doors must be provided either in the sides or cover plate of the kiln to facilitate insertion of the charge and elfectual closing of the kiln. The top or. cover plate is fitted with one or several apertures each fitted with a slide plate or grated damper or other valve arrangements by means of which the area of the aperture or apertures may be varied at will, and it may be fitted with bafiles in e kiln may be and" the burning process.

a charcoal burning chamber according to my invention, and ig. 2 a top plan thereof.

moved and the chamber packed with fagots 1n the usual manner known to charcoal tcm of the charge, as described, the 'ccmbust1on proceeds gradually from the bottom to" the top ofthe charge. And since the only openings for ingress of fresh air and egress of products of combustion are in the top of the kiln the entering air must flow downward through the charge to reach the zone of combustion, while the products of come bustion must pass upward through the unburned part of the charge before finding exit from the. chamber. The control of the fire is in large measure automatic, sincqiii the combustion becomes intense, the upwar" flowing mass of gases passing outward through the to opening or openings repels the inflow of esh air, and the fire is auto matically checked. When the fire is finds opportunity to enter downward notwithstanding the resistance of the outflowi-ng gases and son balance is maintained between the outgoing air and consumed gases and the incoming fresh air. However, by reason of various irregularities, such for example, as variations in the character of the wood, the burning does not always tend to proceed regularly throughout the length. and breadth of the combustion zone, so that it is necessary to watch the drafts and manipulate the vent closures from time to time to influence the direction of the conil mstion and secure its even progress from the bottom of the charge upward. irregularity of the burhing can be} detected byboniparing are preferably insulated with asbestos mill. board, fibro-cement sheeting, or likerrefrac tory materlal to prevent loss of heat during Figure 1 is a'broken sectional elevation of In operation, the lid on coveriA is re It burners and the charge lighted through the bottom doors B, which done, these-v doors.

as shown has vents D and checkedbeyond a certain point, the fresh air I Tilt? the temperatures at different points on the shell of the kiln.

The area of the top opening or openings can be made such in relation to the capacity of the kiln that the amount of fresh air entering, under the automatic control referred to, suffices only for the distillation of the wood, the entrance of the fresh air into the lower zones of converted wood so as to effect its destruction, being avoided. This desired rate of intensity of the combustion is marked by a certain temperature in the walls of the kiln, and by observing the-temperatures and controlling the areas of the vent openings by means of the closures the proper temperature can be maintained and a satisfactory product secured with a minimum of waste. Y

As 'hasbeen stated, the cover or top of the kiln may be provided with one vent or with several, this being determined by the form, capacity, or other characteristics of the kiln. When only one ventis provided the incoming air and, outgoing gases must both pass through it, and obviously this inflow and outflow through the same opening may occur, too, when several vents are pro- 1 vided; in either case there is provision at the top of the kiln for admission of air and exit of gases in such manner that both traverse practically all parts of the raw wood lying above the charcoal, a natural circulation being set up which promotes a uniform progress of combustion throughout the length and breadth of the charge.

Waste of heat by radiation is minimized by providing the kiln with a lining E of fibro cement, asbestos board,'or like refractory material. F are bafiles, the use' of which is optional.

Heretofore the uniform practice of burn-' ing charcoal whether in pits, meilers or built up ovens, was to admit air for combustion at the bottom and sides of the heap and to allow the gases to pass out at the top.

' Such a process inevitably led to one result;

charcoal was produced but it was produced under conditions which insured the immediate destruction of a certain amount of it and consequent loss. This will be understood when it is remembered that in the upward burning of the charge the hottest portion of the fire is always below. When air enters and comes into contact first with the glowing wood, it consumes some of the char-' coal already formed and produces ash and carbonic'acid gas, the gas being a'loss and the .ash a waste. In the case of my'invention the air is brought into contact with the distilling wood only and kept out of contact with the carbonized wood, there being no loss .of carbonized wood andthe distilling process being facilitated.

What I claim as my invention and desire to secure by Letters Patent is 1. The herein described process of manu-' facture of charcoal which consist in inclosing a charge of wood in a chamber, lighting the charge at the bottom thereof, admitting air to and releasing gases of combustion from the charge only at the top thereof, and controlling the rate at which the air is thus admitted and the gases of combustion thus discharged in such manner that the combustion proceeds evenly from bottom to top of the charge While the indraft passes downwardly through all parts of the unburned portion ,of the charge and the gases of combustion pass upwardly through the same.

2. The herein described process of manufacture of charcoal which consists in inclosing a charge of wood in a chamber having a vent or vents in its top, lighting the charge at the bottom thereof, and admitting air to and releasing gases of combustion from the charge only at the top thereof by natural circulation of the air and gases in and out, I 

